Tamper-proof seal



Feb. 4,1969 G. CANTER 3,425,730V

TAMPER-PROOF SEAL Filed June 24, 1966 I N VEN TOR. GEORGE CANTEIR Byfdww (wk ATTORNEY United States Patent Oiiee 3,425,730 Patented Feb. 4, 1969 4 Claims ABSTRACT F THE DISCLOSURE This invention relates to tamper-proof seals of the type 'used to seal containers, trucks, freight cars and other means for transporting, storing or handling goods in which a positive indication is desired as to whether or not the container or the like has been opened by an unauthorized person. Such seals can only be opened after their initial sealing by destroying the seal, thereby giving positive evidence that the closure for the container or car has been tampered with. The main locking feature of the device is a bowed wedge-shaped barbed hook position within a narrow box-like enclosure with a slit type entrance with the sealing means comprising the said hook and an opening on an end of a link or strap adapted to engage the hook, said hook, when flat, being greater than the width of said opening, and when bowed, being able to pass through said opening with close tolerance so that any attempt to tarnper with the seal within the narrow contines of the box will cause the barbs to hatten out and prevent the hook from passing back through the opening.

The usual seal of this type has a strap or link portion which is passed through a loop on a container or car door and a loop on the door frame, and then sealed so that the door cannot be opened without breaking either the strap or loop or the sealing means.

The novelty in this invention lies in the particular sealing means used. In essence, the sealing means comprises an opening on one end of the link or strap of the seal adapted to engage a Wedge shaped hook projection on the other end of the link or strap, said wedge shaped hook projection being positioned within a box or chamber having a narrow slit-type entrance, said wedge shaped hook means comprising a point with a pair of barbs in bowed cross section with the distance between the points of said barbs, when flat, being greater than the width of the opening so that after t'he hook passes through the entrance opening, any attempt to tamper with the seal will cause the barbs to vflatten out and render the hook incapable of passing back through the opening.

Because the aforesaid construction is contained within a box, the only -way to break the seal once it is engaged is either to cut the link or strap or destroy the box within which the barbed wedge .shaped hook is engaged, since it is impossible to disengage the hook by prying or maneuvering without destroying the surrounding box.

The advantages of the construction of the` invention are that the seal cannot be opened without being destroyed, thereby rendering it effectively tamper proof and a means to determine whether or not a door or enclosure of a particular container or car has been opened by unauthorized persons, and a further advantage of the seal is that it requires a breaking to open the door, thereby furnishing evidence that a particular container, car or enclosure has been burglarized.

Further advantages will appear from the specication hereinbelow. The invention is illustrated in the accompanying drawings -in which:

FIG. 1 is a plan view of a blank out of which the invention is made;

FIG. 2 is an elevational view of the blank of FIG. 1 partially folded;

FIG. 3 is a sectional view along the lines 3-3 in FIG. 2;

FIG. 4 is Ia medial cross section of the invention showing it partially installed on a door and door frame with parts cutaway;

FIG. 5 is a medial cross section view similar to FIG. 4 with parts cut way showing the seal in locked position;

FIG. 6 is a top plan view of the seal with parts cut -away showing the relative positions of the locked parts;

FIG. 7 is a view of the locking parts in position similar to FIG. 6; and

FIG. 8 is a View similar to FIG. 7.

Similar numerals refer to similar parts throughout the several views.

The blank 10 is stamped out of metal such as a thin llexible steel ribbon. The central portions comprise a link or strap 12. At the lirst end 14, provision is made for forming a box out of a pair of sheet-like portions 16 and 13 which can be held together by crimping 20. At the rst end 14 there is also a foldable tab portion 22 on which there is wedge shaped hook 24. There is also a cut portion 26, in sheet portion 18, which can be pressed to form a stop 28 and a recessed pocket or dimple 30 in sheet-like portion 16, which will appear in a wall of the box 32.

Box 32 is made by folding tab 22 inwardly and then by folding sheet-like portion 16. After the folds are made, 22 and sheet-like portion 16. After the folds are made, edges 34 are fastened together to form the box by means of crirnps 20 or any other fastening means: known to the art. This type of construction is illustrated in United States Patent No. 3,068,033 granted to George G. C-anter and Gilbert G. Canter on Dec. 11, 1962. When the box is completed, it will have a very narrow entrance 40 forming a limited access opening adjacent the strap portion 12. The second end 42 is somewhat reduced in width so that it may easily be pushed into opening 40.

There is an aperture or opening 44 cut into end 42 which is used as a stacking hole with which to pin or tie several seals together for storage or shipment. Second end 42 also comprises a cutout portion 46 which is adapted to engage hook 24. Cutout portion 46 also has a locking tab 48 which is bent outwardly along fold. line 45 at its leading end to aid in engaging hook 24.

The wedge shaped hook 24 has a point 50 and a pair of barbs 52 and is connected to tab 22 by means of a very narrow strip or neck 54 of metal of the blank 10.

The original metal from which the hook 24 is made is flat. However, during the manufacturing process, hook 24 is bowed. When the metal of the hook is flat, the distance between barbs 52 is approximately .010 of an inch wider than the width of opening 46 at its widest point (leading end 415). This is illustrated in FIG. 6 of the drawings in which the distance between barbs 52, when in flat condition, is represented by imaginary parallel lines F, and the distance between the ends of the widest point `of the opening 46 (leading end 45) is represented by imaginary parallel lines L. In this case, the distance between lines F-F is approximately .010 of an inch longer than the distance between lines L-L.

When hook 24 is bowed as illustrated in FIG. 3 of the drawings, the distance between barbs 52 is smaller than when the hook is in flat condition. This distance is represented by imaginary parallel lines B-B as shown in FIGS. 3, 7 and 8 of the drawings. Thus, in FIG. 7 it can be seen that the distance between lines B-B is less than the distance between lines L-L illustrating that when the hook 24 is in bowed condition, there is some clearance, the preferred clearance being .001 of an inch so 3 that the hook 24 will just clear opening 46 at leadingend 45 permitting the hook to be engaged when end 42 is inserted into box 32.

Reference to FIG. 8 will show that the trailing edge 47 of opening 46 (distance between lines C-C) is much narrower than the distance between the barbs 52 (BGB). This is to prevent disengagement by pushing end 42 forward toward the barbs 52. Thus, the only possible way to disengage the hook 24 once it has been rneshed is to try to push end 42 forward again past the barbs 52 at the widest portion of opening 46, namely leading end 45, and then ease end 42 back after disengaging the hook 24. An effort to do this is frustrated by reason of the fact that the end 42, after insertion, is within the conned area of box 32 at end 14. The point 56 of the hook 24 will be resting within dimple 30 as shown in FIG. 5 of the drawings, and will be directly underneath cut portion 26 forming stop 28 so that when end 42 is moved forward to disengage the barbs 52, it will hit stop 23 because it is Within the confined space of box 32 and will ride up and jam into tab 26. It is impossible by outside manipulation to push hook 42 in any particular way where the barbs 52 can be passed through the widest part of opening 46 again. Any attempt to disengage the barbs 52 by tampering on the outside, for example, by inserting a iiat object like a knife or a screwdriver will, within the narrow confines of box 32, cause barbs 52 to flatten out making hook 24 wider than the widest portion of opening 46 thereby rendering it impossible to again disengage the hook 24 without actually destroying the seal itself.

I also show a cutout portion S centrally along hook 24. This is an optional feature and may or may not be provided in the device depending on the hardness of metal used. The purpose of providing cutout portion Sti is to render flattening of hook 24 easier when a seal made of harder metal is tampered with.

Operation of the device One end of the seal is placed through a loop 62 on a door 63 and a loop 64 on a door frame 65. The strap l2 is then looped around so that the second end 42 may be inserted into the box 32 of first end 14. The device is now n the position as shown in FIG. 4 of the drawings. The second end 42 is then inserted into slit opening 40 in box 32 and pushed forward as far as it can go toward inner end 66 of box 32. Then end 42 is reversed and drawn back. Stop and guide 43 engages point 50 of hook 24. As end 42 is drawn back, point 50 of hook 24 enters opening 46. Dimple 30 is provided to permit hook point 50 to move within the narrow contines of box 32 when being engaged `by opening 46 in end 42. As end 42 continues to be drawn back, it reaches a point where hook 24 is well within opening 46. Barbs 52 and shoulders 68 prevent withdrawal by pushing in either direction. At this point the seal is firmly made. Any attempt to push end 42 inwardly into box 32 will result in hitting stop 28. Pulling out will result in hitting shoulders 68.

The main locking feature of the device is the bowed, wedge shaped, barbed hook 24 positioned between stop 28 and dimple 30. Its function as described is protected by the box 32, preventing disengagement of said hook 24 by any tampering means without destroying the box 32 and the entire seal.

While I have described my invention in its preferred forms, there may be other forms which it may take without departing from the spirit and scope of the invention, and I, therefore, desire to be protected for all forms coming within the scope of the claims hereinbelow.

Wherefore I claim:

1. A tamper-proof seal having a main body portion comprising a strap portion and a pair of ends, a first end of said strap portion comprising a shallow box having a narrow opening, said shallow box comprising a top wall and a bottom wall, said walls being connected together at all edges except the portion of the edge having the narrow opening, a dimple located in one of said walls and catch means located in the other` of said walls with hook means positioned between said walls and between said dimple and said catch means, said hook means comprising a pair of barbs at its widest portion, said barbs being normally bowed transversely, hook engaging means on the second end of the strap comprising a cutout portion having a wider portion and a narrower portion adapted to iit at its widest part in close tolerance over the barbs of the hook means, said second end of said strap portion being adapted to enter said narrow opening and to engage said hook means with said hook engaging means.

2. The tamper-proof seal as defined in claim 1, in which the said catch means located in the second mentioned side wall extends inwardly into the box of the seal, and is normally in facing relationship with said second end of said strap when engaged to said hook means.

3. A tamper-proof seal comprising a strap portion made of a stiff flexible material with the ends of said strap portion comprising locking means, a first end of said strap including a pair of spaced sheets with a hook comprising a point and at least one pair of barbs positioned between them, said spaced sheets being connected to form an enclosed chamber having a limited access opening on one side, said hook being mounted from one of said sheets with the other sheet having a dimple forming an inner recess with said inner recess positioned relatively near the point of said hook so that if the point of said hook is moved toward the said recess, it will move within the said recess; catch means formed on the sheet opposite the dimpled sheet extending inwardly toward the recess of said dimple, with the point of the hook positioned relatively between the dimple and the catch means, hook engaging means on the second end of the strap comprising a locking projection associated with a cutout portion, said barbs of said hook being normally bowed transversely and being relatively narrower in close tolerance than the width of said cutout portion at its widest point, said hook engaging end of said strap being adapted to slide t into said limited access opening of said hook chamber whereby when said hook engaging end is slide fitted into said hook chamber and reversed, said hook engaging means will engage the point of the hook and the barbs of the hook will pass through the hook engaging means to lock the seal permanently.

4. The tamper-proof seal as defined in claim 3, in which said catch means formed on the sheet opposite the dimpled sheet are positioned in faced relationship to said second end of said strap when said hook engaging means have engaged said hook to lock the seal.

References Cited UNITED STATES PATENTS 908,186 12/1908 Wing 292-321 1,030,458 6/1912 Brooks 292-320 2,804,333 8/1957 Canter 292-317 MARVIN A. CHAMPION, Primary Examiner.

E. MCCARTHY, Assistant Examiner. 

